The present invention is an improvement of a control apparatus for the application and release of a hand brake as described in U.S. Pat. No. 6,394,559 to Ring et al. This patent is incorporated in this application by reference thereto.
In prior art hand brake control systems the setting of the hand brake was not directly sensed, but rather a sequence of valve closings and openings was performed. While this is satisfactory for virtually all operations, the failure of, for example, certain hydraulic lines and connections would go undetected, and the hand brake would not be applied although it would be assumed to have been applied.
Therefore, it can be appreciated that a direct sensing of the position of a movable element in a regulating valve of the control system is desirable.